AR stuff ??

See:

https://developer.vuforia.com/library/a ... he-Gear-VR

Right, but that isn't cost efficient :)

While on the subject, is there a way to make pass-through view perform in real-time and not lag horribly? (reduce resolution for example somehow; etc.)

Well.. you didn't specify cost efficient...

For non-cloud - It is free if you show the watermark, or $500 for the classic plan to remove the watermark.

Without the AR and just camera pass through, the Unity wecam texture will work (and you can select the resolution you want). It's had real performance problems in the past, but maybe you can concept your idea.

Otherwise you'll want to access the camera via a plugin.

Is there such plugin in existence ?

I wonder if Unity wecam texture (assuming it has no performance issues in low res) can be used for positional tracking (using markers on the walls).